Short-duration exercise and confinement alters bone mineral content and shape in weanling horses.

This research study examines the hypothesis that short-duration exercise can reduce the decrease in bone mass in confined weanling horses.

Research Background

The research aimed to test if short-duration exercise could counteract bone mass loss often observed in confined young horses. The test subjects included 18 quarter horses, comprised of nine male and nine female weanlings weaned at 4 months old. These weanlings were put in box stalls and made to adjust for 5 weeks before the commencement of the research study.

Research Methodology

The weanlings were divided into three different treatment groups post the adjustment period:

• Group housed: This group of horses were housed together and had free access to exercise in a 992 m2 drylot.
• Confined with no exercise: Horses in this group were kept in 3.7 m x 3.7 m box stalls for the whole duration of the trial without any exercise regime.
• Confined with exercise: This group of horses were also kept in 3.7 m x 3.7 m box stalls, but unlike the earlier group, they were subjected to a sprint of 82 m/day, 5 days/week.

Data Collection and Analysis

To assess changes in bone mineral content and cortical widths, dorsopalmar and lateromedial radiographs of the left third metacarpal bone were taken on 0, 28, and 56 days. The team then evaluated the mean values of medial, lateral, and total radiographic bone aluminum equivalence, as well as dorsal and palmar radiographic bone aluminum equivalence over time.

Results

The results indicated that mean values of medial, lateral, and total radiographic bone aluminum equivalence increased over time, while dorsal and palmar radiographic bone aluminum equivalence did not significantly change. When comparing treatment groups, it was observed that dorsal, medial, and total radiographic bone aluminum equivalence tended to differ with exercised horses showing an increase in their respective values over time. On the other hand, confined horses showed a decrease in normalized medial and total radiographic bone aluminum equivalence over time.

Moreover, the research observed a significant change in the dorsopalmar cortical width in exercised horses, and a decrease in dorsopalmar medullary cavity when compared with group-housed horses. Additionally, dorsal and medial cortical width seemed to increase only in the exercised horses.

Conclusion

In conclusion, this study supports the hypothesis that short-duration exercise may counteract the decrease in bone mass typically observed in confined young horses and could be effective in improving bone mass, and therefore, the skeletal strength of horses.